Pump mechanism



R. MULLER PUMP MECHANISM Dec. 19, 1961 5 Sheets-Sheet 1 Filed May 20, 1957 s l 1 ii INVENTOR. RUDOLF MULLER ATTORNEYS Dec. 19, 1961 R. MULLER 3,0 ,5

PUMP MECHANISM Filed May 20, 1957 3 Sheets-Sheet 2 FIG.3

INVENTOR. RUDOLF MULLER A TTORNEYS R. MULLER PUMP MECHANISM Dec. 19, 1961 3 Sheets-Sheet 3 Filed May 20, 1957 United States Patent Ofiice 3,013,503 Patented Dec. 19, 1961 3,013,503 PUMP MECHANISM Rudoif Miiiler, Leverkusen, Germany Filed May 20, 1957, Ser. No. 660,300 Claims priority, application Germany May 28, 1956 7 Claims. (Cl. 103-235) Considerable difficulties arise when conveying corrosive liquids which in addition have solids of varying size suspended in them. The reciprocating or rotating delivery elements of pumps used for this purpose and also the stufiing boxes are subject to heavy wear. Furthermore, the valves require constant maintenance and repair, since leaks are caused by corrosion and the satisfactory operation of the valves is impeded by solids.

The present invention has for its object to provide a pump mechanism which satisfies the following conditions:

(1) It has no moving parts which come into contact with the liquid,

(2) It has no stufiing boxes,

(3) It has no valves which operate within the liquid,

(4) The parts thereof which come into contact with the liquids are of a simple design and thus economical,

(5) It has a large delivery head.

If the various proposals for a reliable design of pump are examined on the basis of these requirements, it is established that most designs only satisfy one of the said requirements.

FIG. 1 is a diagrammatic view of one known type of air-lift pump.

FIG. 2 is a diagrammatic view of one form of pump mechanism according to the invention.

FIG. 3 is a diagrammatic view of a modified form of pump mechanism.

FIG. 4 is a diagrammatic view of a further embodiment of the pump mechanism.

One known type of construction, the so-called air-lift pump (see FIG. 1), approximately satisfies the conditions set forth above. A rising pipe 2 is immersed to a depth H in the liquid 1 which is to be conveyed, which liquid has the specific gravity p Compressed air is blown into the bottom end of this pipe through the pipe 3. The mean specific gravity p of the liquid filling the pipe 2 is thus reduced, so that the pipe is filled to the height H in accordance with the law of communicating pipes H p =H p It follows from this that the depth of immersion H must be made as large as possible in order to obtain a high delivery or pressure head without considerably lowering the volume p using large volumes of compressed air. The depth of immersion is limited by the size of the vessel containing the liquid 1, so that only small pressure heads can be achieved. Moreover, the air-lift pumps easily become clogged by the solids in the liquid which is to be conveyed.

The known air-lift pumps or liquid siphons require two valves which operate within the liquids. These valves are exposed to the danger of corrosion and of becoming clogged and therefore they do not comply with the third conditionindicated above.

The pump mechanism which is proposed according to the invention and which complies With all five conditions is shown in PEG. 2. A container 4 is immersed in the liquid 1 which is to be conveyed, the top" of said container being provided with an opening 5. The container 4 is also provided with a pipe 6 which projects a slight distance into saidcontainer and a pipe 7 which terminates just above the bottom thereof. The pipe 6 is connected to a three-way valve 8, which valve 8 has two switching positions; either the container 4 is connected through the pipe 6 to the compressed air pipe 9 or the container is in communication with atmosphere through the pipe 10.

The three-way valve 8 can be moved manually or by an automatic mechanism. An electromagnetic drive is illustrated by way of example in FIG. 2. A slowly rotating disc 11 closes the contact 13 by means of the cam 12, so that electric current flows through the coil 14 and changes over the valve '8.

The pump mechanism operates with a two-phase cycle. in the first phase, the liquid 1 flows through the opening 5 into the container 4 and the displaced air escapes through the pipe 6 and the pipe 10 to atmosphere. In the second phase, the three-way valve 8 is changed over and compressed air flows through the pipe 6 into the container 4. Some of the air escapes by way of the opening 5. A pressure is set up in the container 4, the value of this pressure depending on the ratio of the flow resistances in the valve 8 and the pipe 6 on the one hand and the opening 5 on the other hand. By means of this pressure, the liquid which has entered the container 4 in the first phase is conveyed through the pipe 7 into the tank 15. For example, when the flow resistances in the pipe system (8 and 6) and the opening 5 are the same, the pressure in the vessel 4 amounts to half the pressure of the compressed air in the pipe 9. With a compressed air pressure of 3 atm. gauge, there is thus produced a delivery pressure of 1.5 atm. gauge and a pressure head of approximately 15 metres. However, if the opening 5 is clogged by a solid body during the first phase, the full compressed air pressure operates in the vessel 4 until the opening 5 is again cleared.

If the opening 5 is chosen to be larger, it is possible to shorten the time for the first filling phase, since the container 4 is filled more quickly. In such a case, more liquid is conveyed per unit of time, but only up to a smaller head of pressure, since the pressure developing in the container 4 during the second or pump phase is smaller.

In order to increase the pump capacity, it is possible to evacuate the container 4 during the first or filling phase. An example of this arrangement is shown in FIG. 3. Connected to the pipe 6 is a jet apparatus 16, which is operated with compressed air. In the first phase, the valve 17 is open, the container 4 is evacuated and the liquid 1 which is to be conveyed flows in through the opening 5. In the second or pump phase, current flows through the coil 18 by way of the contact 13, and thus the valve 17 is closed and the compressed air flows through the pipe 6 into the container 4 and the liquid situated in the said container is delivered by way of the pipe 7.

In the above described embodiments, the first and second phases were controlled by a rotating disc formed with a cam. It is, however, possible to initiate the first and second phases by means of level indicators fitted to the container 4, which initiate the first or filling phase when the level falls below a predetermined level and start the second or delivery phase when a predetermined upper level is exceeded.

Accordingly, FIGURE 4 illustrates an embodiment of the invention including two level indicators which act as' venting means to cause the container to be filled with liquid when substantially empty during a filling. phaseand to cause the liquid to be pumped out when substantially full during a pumping phase.

FIGURE 4 shows an upper level indicator including a determined lower point on the inside wall of container 4. Container 4 in. this embodiment is similarly .-p.ro-, vided with opening '5, pipes 6 and7, jet chamber-16, and

valve 17. v

Adjacent pivotablefioatie is positioned a contact 27 Upon completion of one filling phase, when container 4 has become filled to a pre-determined upper level, float 23 will be urged into abutment with contact 27 to close a first circuit. On the other hand, when said liquid level falls below said pre-determined level, float 23 is displaced from urging abutment with contact 27, thereby opening said first circuit.

Adjacent float 24 is contact 29. When the level of the liquid in container 4 is substantially at or above that indicated at 28, contact 29 remains closed energizing a circuit through contact 33 and relay 31. Upon completion of a pumping phase when the level of liquid in container 4 generally falls below the level indicated at 28, float 24 abuttingly urges against contact 29, opening the same.

When contact 27 is closed the first circuit through line 30 energizes relay 31 causing the closing of both contact 33 and contact 34. This, in turn, completes the circuit through contact 34 to electromagnet coil 18 whereby valve 17 is caused to close. Since contact 29 is normally closed until the level of the liquid falls below the level of 28 in the pumping phase, the second circuit, including contact 28, contact 33, and relay 31, is also closed. In this connection it will be remembered that contact 27 is closed when the liquid in container 4 reaches the pre-determined upper level.

When valve 17 is thus closed, the compressed gas entering jet chamber 16 is conducted through pipe 6 into container 4 to commence a pumping phase. Accordingly, the passage of the liquid in container 4 through pipe 7 is initiated in the afore-described manner.

As a consequence float 23 is displaced from abutment with contact 27 causing the first circuit through line 30 and relay 31 to be broken. Nevertheless, since contact 29 remains closed, the second circuit, through contact 29, and contact 33, and relay 31 remains closed. Inasmuch as relay 31 includes an electromagnet element, since the same is energized, the contact 33 and contact 34 both remain closed. Consequently electromagnet 18 remains energized until the liquid in the container falls below the level indicated at 28. When this occurs, float 24 causes contact 29 to open breaking the second circuit, through contact 33 to relay 31 and through contact 34 to electromagnet 18.

At this point the pumping phase ends and the filling phase begins as valve 17 is opened permitting the compressed gas to pass through jet chamber 16 and valve 17. This generates an evacuation pressure within container 4 via pipe 6 through which the gas within container 4 is evacuated. As a result of such evacuation additional liquid is caused to enter opening to again fill container 4 in a filling phase. When the level of the liquid in container 4 reaches the pre-determined upper level, float 23 is once more urged into abutment with contact 27 to close the first circuit. In this manner the pumping phase begins and the cycle is repeated.

It will be appreciated that the particular float and relay means and the particular circuitry for actuating valve 17 in response to the indication of the disposition of the liquid level in container 4 is not critical to the invention but is merely illustrative of a particular manner in which the same may be carried out.

I claim:

1. A pump mechanism comprising a substantially liquid-tight container adapted to be immersed below the surface of a body of liquid to be pumped, a valveless opening defined through the top of said liquid-tight container, 21 first conduit in flow-communication with the upper portion of said container, a valve-free second conduit in [lowcommunication with the lower portion of said container, the flow resistances of said opening with respect to the flow resistances of said first conduit being such as to reduce the delivery pressure, whereby said container is filled more rapidly and a greater amount of liquid is conveyed by said pump mechanism per unit of time, and means for, in sequence, first venting said first conduit to allow filling of said container through said opening and then passing compressed gas through said first conduit into said container, forcing liquid therefrom through said second conduit.

2. Pump mechanism according to claim 1, in which venting means include a three-way valve, manually controllable.

3. Pump mechanism according to claim 1, in which the means for venting said first conduit include means for applying reduced pressure to said first conduit.

4. Pump mechanism according to claim 3, in which said means for venting said first conduit is a jet pump, said jet pump being provided with a valve for controlling the exhaust of said pump, whereby, when said valve is open, the container is evacutaed and the liquid is allowed to flow into said container, and when said valve is closed, delivery pressure is produced in said container forcing the liquid out of said container.

5. Pump mechanism according to claim 4, in which said valve controlling the jet pump is closed by electric contact.

6. Pump mechanism according to claim 1 wherein the said means for first venting and the second passing compressed gas through said first conduit includes an electromagnetic relay and an electric contact means.

7. Pump mechanism according to claim 1, in which said container is provided with level indicating means adapted to actuate said venting means whereby said container is evacuated and the container caused to be filled with liquid during a first phase when the level of the liquid has fallen below a predetermined level and with level indicating means adapted to initiate a second phase when an upper predetermined level is reached whereby the liquid is delivered out of the container.

References Cited in the file of this patent UNITED STATES PATENTS 

